Cylinder cleaning device

ABSTRACT

It is an object of the invention to provide a cylinder cleaning device which is suitable for downsizing the printing press. 
     The thick portions 10 b,  10 c  of the pressure pad  10  are mounted on the grooved portions  42, 43  of the support bar  40.  The engaged portions of the side plate  50  are disposed on the opposite sides of the thick portions  10   b,    10   c . The pressure pad  10  and the support bar  40  are nipped between and held by the engaged portions.

TECHNICAL FIELD

The present invention relates to a cylinder cleaning device for cleaning a cylinder provided on a printing press. In particular, the present invention relates to the cylinder cleaning device which presses a cleaning fabric against the surface of the cylinder with a pressure pad to clean it.

BACKGROUND ART

A printing press includes a plurality of cylinders and prints a newspaper and the like. The surface of the cylinder must be cleaned often to remove residual ink or stain such as paper dust and the like.

A cylinder cleaning device is used to clean the surface of the cylinder. The cylinder cleaning device is built in the printing press. There exist several types of the cylinder cleaning device. The most typical cylinder cleaning device uses a cleaning fabric. The cylinder cleaning device presses the cleaning fabric against the surface of the rotating cylinder with a pressure pad and wipes the surface of the cylinder with the cleaning fabric. FIG. 18 is an explanatory view illustrating the prior cylinder cleaning device using the cleaning fabric.

The cylinder cleaning device 1 opposes to the cylinder 100 as the cleaning object.

The cleaning fabric 4 is supplied from a supply roll 2 and taken up onto a take up roll 5 through the pressure pad 10. A solenoid 8 presses the pressure pad 10 against the cylinder 100 and moves the pressure pad 10 away from the cylinder 100. The cleaning fabric 4 is engaged with and moved away from the surface of the cylinder 100 by the forward and backward movement of the pressure pad 10.

The pressure pad 10 is made of elastic material such as nitrile rubber. The pressure pad 10 includes thick portions 10 b, 10 c at opposite edges thereof. Clamp bars 11, 12 include clamp grooved portions 11 a, 12 a for mounting and fixing the thick portions 10 b, 10 c of the pressure pad 10. A pressure portion 10 a is formed in the pressure pad 10 mounted by the clamp bars 11, 12. The pressure portion 10 a is shaped to be generally semi-cylindrical.

The contact area between the cleaning fabric 4 and the cylinder 100 is dependent on the radius of the generally semi-cylindrical of the pressure portion 10 a. The contact area is small when the radius of the pressure portion 10 a is small, while the contact area is large when the radius 10 a is large. The radius of the pressure portion 10 a must be predetermined appropriately.

Meanwhile, a space for installing the cylinder cleaning device 1 nearby the cylinder 100 is required to be small recently for downsizing the printing press and realizing high density. For example, the cylinder 100 which should be cleaned may be disposed behind the space between other cylinders 101, 102. It is difficult to pass the cylinder cleaning device 1 including the pressure portion 10 a having an appropriate radius through the space between the cylinders 101, 102 in the prior art.

Patent Document 1 (EP0936068A) discloses a prior structure for engaging the pressure pad with the clamp bars. Patent Document 2 (EP1000740A) discloses a more detail structure of the prior cylinder cleaning device 1 as shown in FIG. 18. Patent Document 3 (U.S. Pat. No. 7,287,297) discloses another structure for engaging the pressure pad with the clamp bars. In the cylinder cleaning device shown in Patent Document 1, Patent Document 2 and Patent Document 3, the engaging portion between the pressure pad and the clamp bars projects from the outer surface of the generally semi-cylindrical pressure portion. As a result, the pressure pad becomes too big to be installed in the small space.

Patent Document 4 (U.S. Pat. No. 5,878,669) discloses that the cylinder cleaning device can be used in a smaller space than the others. In the cylinder cleaning device, when the pressure portion of the pressure pad engages with the outer surface of the cylinder, a pulling and removing force acts on the pressure pad to pull and remove it. The structure for fixing the pressure pad cannot resist the pulling and removing force.

Patent Document 1: EP0936068A

Patent Document 2: EP1000740A

Patent Document 3: U.S. Pat. No. 7,287,297

Patent Document 4: U.S. Pat. No. 5,878,669

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

It is, therefore, an object of the present invention to provide a cylinder cleaning device which is suitable for downsizing the printing press and realizing high density.

Solution to the Problems

A cylinder cleaning device cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder. The device comprises a pressure pad made of elastic material and including a pressure portion engaged with the back surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad. The pressure portion is interposed between and formed integrally with the thick portions. The device comprises a support bar including grooved portions formed in the opposite sides thereof and extending longitudinally of the support bar. The thick portions are fitted into the grooved portions so that the pressure pad can be mounted on the support bar. The device comprises a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof. The pressure pad and the support bar are nipped between and held by the engaged portions.

The device further comprises following elements.

The pressure pad is plate-shaped. The pressure portion is bent to be generally semi-cylindrical so that the thick portions oppose to each other to be fitted into the grooved portions when the pressure pad is mounted on the support bar.

The pressure portion is generally semi-cylindrical. The thick portions are opposed to each other to be fitted into the grooved portions.

The side plate include an opening on one side. The pressure pad and the support bar are received in the opening.

The pressure pad and the support bar are nipped between the engaged portions on opposite sides thereof.

The device can be comprised as follows.

The pressure pad includes a pressure portion, a pair of thick portions and a pair of connecting portions. The pressure portion is disposed on the center of the pressure pad. The thick portions are disposed on the opposite edges of the pressure pad. The connecting portions are interposed between the pressure portion and the thick portions. The connecting portions connect the pressure portion with the thick portions and being thinner than the thick portions. The pressure portion, the thick portions and the connecting portions being made of elastic material and formed integrally.

The support bar includes a base portion and a pair of grooved portions. The base portion extends longitudinally of the support bar. The grooved portions are formed in the opposite sides of the base portion to extend longitudinally of the support bar and having depths corresponding to the thicknesses of the thick portions and corresponding to the thicknesses of the connecting portions so that the thick portions and the connecting portions can be fitted into the grooved portions. The thick portions and the connecting portions include outer surfaces disposed to be flush with the opposite sides of the base portion when the thick portions and the connecting portions are fitted into the grooved portions.

The side plate includes engaged portions engaged with the opposite side surfaces of the base portion and the outer surfaces of the thick and connecting portions.

The thick portions project toward the grooved portions from the inner surface of the connecting portions.

EFFECT OF THE INVENTION

In the present invention, the thick portions of the pressure pad are fitted into the support bar. The thick portions and the support bar are nipped by the side plate on opposite sides thereof. The thick portions and the support bar are not projected respectively from the outer surface of the generally semi-cylindrical pressure pad. As a result, the present invention can provide the cylinder cleaning device which is suitable for downsizing the printing press and realizing high density.

When the pressure pad along with the cleaning fabric is pressed against the outer surface of the cylinder, the strong pulling and removing force acts on the pressure pad to pull and remove it. However, the pulling and removing force on the pressure pad disperses and acts on the side plate. As a result, the side plate can keep the pressure pad on the support bar rigidly even though it is thin. The side plate can have a minimum thickness to keep it. As a result, the present invention can provide the cylinder cleaning device which is more suitable for downsizing the printing press and realizing high density.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic view illustrating an embodiment of the present invention.

FIG. 2 is an enlarged view illustrating the support bar.

FIG. 3 is a perspective view illustrating the first embodiment of the pressure pad.

FIG. 4 is a perspective view illustrating the second embodiment of the pressure pad.

FIG. 5 is a perspective view illustrating the first embodiment of the side plate.

FIG. 6 is a perspective view illustrating the second embodiment of the side plate.

FIG. 7 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 8 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 9 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 10 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 11 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 12 is an explanatory view illustrating the assembly process of the pressure pad, the support bar and the side plate.

FIG. 13 is a sectional view illustrating the third embodiment of the pressure pad.

FIG. 14 is a sectional view illustrating the fourth embodiment of the pressure pad.

FIG. 15 is a sectional view illustrating the fifth embodiment of the pressure pad.

FIG. 16 is a sectional view illustrating the sixth embodiment of the pressure pad.

FIG. 17 is a sectional view illustrating the seventh embodiment of the pressure pad.

FIG. 18 is a schematic view illustrating a prior cylinder cleaning device.

BEST MODE FOR CARRY OUT THE INVENTION

FIG. 1 is a schematic view illustrating an embodiment of the present invention. A cylinder cleaning device can clean a cylinder 100 with a cleaning fabric 4. The device includes a pressure pad 10. The pressure pad 10 includes a pressure portion 10 a and thick portions 10 b, 10 c. The pressure portion 10 a is interposed between the thick portions 10 b, 10 c. The thick portions 10 b, 10 c are disposed on the opposite edges of the pressure pad 10. The pressure portion 10 a and the thick portions 10 b, 10 c are formed integrally and made of elastic material. The pressure pad 10 includes the pressure portion 10 a, a pair of thick portions 10 b, 10 c and a pair of connecting portions 10 d, 10 e. The pressure portion 10 a is disposed on the center of the pressure pad 10. The thick portions 10 b, 10 c are disposed on the opposite edges of the pressure pad 10 respectively. The connecting portions 10 d, 10 e are interposed between the pressure portion 10 a and the thick portions 10 b, 10 c respectively. The connecting portions 10 d, 10 e connects the pressure portions 10 a with the thick portions 10 b, 10 c respectively. The connecting portions 10 d, 10 e is thinner than the thick portions 10 b, 10 c. The pressure portion 10 a, the thick portions 10 b, 10 c and the connecting portions 10 d, 10 e are made of elastic material and formed integrally. Supporting portions 10 f are interposed between the pressure portion 10 a and the connecting portions 10 d, 10 e respectively. The pressure portion 10 a, the thick portions 10 b, 10 c, the connecting portions 10 d, 10 e and the supporting portions 10 f are made of elastic material and formed integrally. The pressure portion 10 a and the thick portions 10 b, 10 c are connected by the connecting portions 10 d, 10 e and the supporting portions 10 f. The supporting portions 10 f are interposed between the pressure portion 10 a and the thick portions 10 b, 10 c. The supporting portions 10 f support the pressure portion 10 a to the thick portions 10 b, 10 c by the elastic force.

The device includes a support bar 40. The support bar 40 has grooved portions 42, 43. The grooved portions 42, 43 receive the thick portions 10 b, 10 c of the pressure pad 10 which are fitted into the grooved portions 42, 43. The device includes a side plate 50. The side plate 50 is disposed on the opposite sides of thick portions 10 b, 10 c and the connecting portions 10 d, 10 e of the pressure pad 10. The side plate 50 receives the thick portions 10 b, 10 c and the connecting portions 10 d, 10 e of the pressure pad 10, and the support bar 40. The side plate 50 includes engaged portions disposed on the opposite sides of the thick portions 10 b, 10 c and engaged with the side surfaces thereof. The support bar 40 has opposite side surfaces 46, 47 parallel to each other. The opposite side surfaces 46, 47 are face-contacted with the inner side surface of the side plate 50.

The device includes a solenoid 8. The solenoid 8 has a piston rod 81. The piston rod 81 is linked with the support bar 40. The cleaning fabric 4 is interposed between the pressure pad 10 and the cylinder 100. If the solenoid 8 is operated, the pressure pad 10 moves forward and backward to the cylinder 100. As a result, the cleaning fabric 4 is pressed by the pressure portion 10 a of the pressure pad 10 to wipe the surface of the cylinder 100.

As shown in FIG. 1, the pressure pad 10 is mounted on the support bar 40. And then the pressure pad 10 and the support bar 40 are nipped by the engaged portions of the side plate 50 on opposite sides thereof. As a result, the pressure portion 10 a of the pressure pad 10 is bent and shaped to be generally semi-cylindrical. The generally semi-cylindrical pressure pad 10 has an outer surface which is disposed inwardly of the outer surface of the side plate 50.

FIG. 2 is an enlarged cross-sectional view illustrating the support bar 40. As shown in FIG. 2, the grooved portions 42, 43 are formed to receive the thick portions 10 b, 10 c of the pressure pad 10. The support bar 40 includes pressure pad shape holding walls 44. The pressure pad shape holding walls 44 are disposed adjacent the grooved portions 42, 43 respectively. The pressure pad shape holding walls 44 are formed to receive the pressure pad 10 when the thick portions 10 b, 10 c of the pressure pad 10 are fitted into the grooved portions 42, 43. The support bar 40 includes a base portion 41. As shown in FIG. 1, the outer surface of the base portion 41 and the pressure pad 10 are flush with each other when the pressure pad 10 is mounted on the support bar 40. Grooved portions for the connecting portions 10 d, 10 e are formed by the pressure pad shape holding walls 44, and the thick portions 10 b, 10 c and the connecting portions 10 d, 10 e can be fitted into and mounted on the grooved portions 42, 43, 44. The outer surfaces of the thick portions 10 b, 10 c and the connecting portions 10 d, 10 e, and the opposite side surfaces 46 of the base portion 41 are flush with each other when be fitted.

The connecting portions 10 d, 10 e are nipped between the side plate 50 and the support bar 40, and reaches the thick portions 10 b, 10 c. The thickness of the connecting portions 10 d, 10 e may be even or may grow adjacent the thick portions 10 b, 10 c but thinner than the thick portions 10 b, 10 c as above stated. The supporting portions 10 f are interposed between the pressure portion 10 a and the connecting portions 10 d, 10 e not to be nipped between the side plate 50 and the support bar 40.

The thick portions 10 a, 10 b project from the inner surface of the connection portions 10 d, 10 e to be fitted into the grooved portion 42, 43. When the thickness of the connecting portions 10 d, 10 e grows adjacent the thick portions 10 b, 10 c, the thickness growing portions project from the inner surface of the other portions to fit the pressure pad shape holding walls 44.

As shown in FIG. 1, the pulling and removing force acts on the pressure pad 10 when the pressure pad 10 presses the cleaning fabric 4 against the cylinder 100, by reason of the friction force between the cleaning fabric 4 and the cylinder 100 being large. The pulling and removing force on the pressure pad 10 acts to pull the pressure pad 10 from the support bar 40. As a result, the pulling and removing force acts to spread the side plate 50 outwardly thereof. However, the pulling and removing force on the pressure pad 10 disperses on the support bar 40. The side plate 50 has a strength not to pull the pressure pad 10 out of the support bar 40 when the pulling and removing force acts on the pressure pad 10. The side plate 50 may be formed by a metal plate.

The support bar 40 includes a through-hole 45 which passes through the base portion 41. As shown in FIG. 1, the side plate 50 is generally U-shaped in cross-section and has an opening on one side. The side plate 50 can receive the pressure pad 10 along with the support bar 40. The side plate 50 has holes (not shown) corresponding to the through-holes 45 of the support bar 40 in position when receiving the support bar 40. The support bar 40, the pressure pad 10 mounted on the support bar 40, and the side plate 50 are fixed by a fixing bolt 60. The base portion 41 of the support bar 40 or the side plate 50 includes means for connecting the piston rod 81 (not shown).

FIG. 3 illustrates the first embodiment of the pressure pad 10. As shown in FIG. 3, the pressure pad 10 is generally flat plated. The pressure pad 10 is totally made of elastic material such as rubber. The pressure pad 10 has the generally flat-shaped pressure portion 10 a before being mounted on the support bar 40. The pressure portion 10 a becomes generally semi-cylindrical when the pressure pad 10 is mounted on the support bar 40. Since the pressure pad 10 is bent and mounted on the support bar 40, the pressure portion 10 a can have a variety of radiuses according to the diameter of the support bar 40 advantageously.

FIG. 4 illustrates the second embodiment of the pressure pad 10. As shown in FIG. 4, the pressure pad 10 is generally semi-cylindrical. The pressure pad 10 has the generally semi-cylindrical pressure portion 10 a before being mounted on the support bar 40. The generally semi-cylindrical pressure portion 10 a can be easily mounted on the support bar 40 advantageously.

FIG. 5 illustrates the first embodiment of the side plate 50. As shown in FIG. 5, the side plate 50 is generally U-shaped in cross-section. The side plate 50 has the opening on the one side. The opening receives the support bar 40 and the pressure pad 10 mounted on the support bar 40. The outer sides of the thick portions 10 b, 10 c of the pressure pad 10 and the base portion 41 of the support bar 40 are flush with each other. As a result, the side plate 50 can easily receive the support bar 40 along with the pressure pad 10.

FIG. 6 illustrates the second embodiment of the side plate 50. As shown in FIG. 6, the side plate 50 comprises the first side plate 501 and the second side plate 502. Since the first side plate 501 and the second side plate 502 are separated from each other, the support bar 40 can be designed without changing the side plate 50 advantageously.

As shown in FIGS. 5 and 6, the base portion 41 of the support bar 40 is nipped by the side plate 50 on the opposite sides thereof. The thick portions 10 b, 10 c of the pressure pad 10 are nipped and fixed between the grooved portions 42, 43 of the support bar 40 and the side plate 50. The side plate 50 nips the base portion 41 of the support bar 40 on the opposite sides thereof to be face-contacted with the base portion 41 and mounted thereof. The thick portions 10 b, 10 c of the pressure pad 10 are nipped and fixed between the grooved portions 42, 43 of the support bar 40 and the side plate 50.

FIGS. 7, 8, 9 and 10 are explanatory views illustrating the assembly process of the flat plate shaped pressure pad 10 shown in FIG. 3, the support bar 40 and the side plate 50. FIGS. 7 and 8 are explanatory views illustrating the assembly process of the pressure pad 10 and the support bar 40. As shown in FIGS. 7 and 8, the thick portion 10 b of the pressure pad 10 is fitted in the grooved portion 42 of the support bar 40, and the thick portion 10 c is fitted in the grooved portion 43. The pressure pad 10 has the portions 10 g which are the outer surfaces of the pressure pad 10 with which the side plate 50 is engaged. The portions 10 g and the outer surfaces of the base portion 41 are flush with each other. FIG. 9 is an explanatory view illustrating the assembly process of the side plate 50 and the support bar 40 along with the pressure pad 10. As shown in FIG. 9, the side plate 50 receives the support bar 40 along with the pressure pad 10.

FIGS. 11 and 12 are explanatory views illustrating the assembly process of the generally semi-cylindrical pressure pad 10 shown in FIG. 4 and the support bar 40. As shown in FIG. 11, when the pressure pad 10 is mounted on the support bar 40, the supporting portions 10 f and the thick portions 10 b, 10 c of the pressure pad 10 are spread. Therefore, the pressure pad 10 can be mounted easily and quickly. FIG. 12 illustrates the support bar 40 along with the pressure pad 10. The pressure pad 10 is kept to be combined with the support bar 40 if being generally semi-cylindrical. As a result, the side plate 50 can be mounted easily.

As shown in FIG. 10, the side plate has holes 51. The holes 51 is aligned with the through-hole 45 of the support bar 40 when the side plate 50 receives the support bar 40. The fixing bolt 60 and a nut 61 nip and fix the side plate 50 and the support bar 40. The fixing means for fixing the side plate 50 and the support bar 40 may comprise an adhesive material. However, since the pressure pad 10 must be, replaced sometimes, the detachable fixing means such as a set of the bolt 60 and the nut 61 is preferable.

FIG. 13 illustrates the third embodiment of the pressure pad 10. As shown in FIG. 13, the thick portions 10 b, 10 c of the pressure pad 10 is generally circle-shaped in cross-section. As a result, it is advantageous that the pressure pad 10 can be mounted on the support bar 40 and the side plate 50 by using the elastic force of the pressure pad 10. That is to say, the cylindrical thick portions 10 b, 10 c of the pressure pad 10 should have the slightly larger diameter than the grooved portions 42, 43 of the support bar 40. As a result, the thick portions 10 b, 10 c can be deformed elastically and engaged with the inner wall of the grooved portions 42, 43 when being mounted on the support bar 40 and fixed by the side plate 50.

FIG. 14 illustrates the fourth embodiment of the pressure pad 10. The pressure pad 10 has a pipe 13 extending longitudinally thereof in the pressure portion 10 a thereof. The pressure pad 10 has a plurality of nozzle holes 14 which are spaced at a distance. A cleaning liquid is supplied in the pipe 13 to be sprayed from the nozzle holes 14. As a result, it is possible to supply the cleaning liquid toward the cleaning fabric engaged with the pressure portion 10 a.

FIG. 15 illustrates the fifth embodiment of the pressure pad 10. The pressure pad 10 has the supporting portions 10 f and the pressure portion 10 a which have thicknesses different from each other. The pressure portion 10 a is thicker than the supporting portions 10 f. That is to say, the pressure portion 10 a is thicker than the pressure portion 10 a and the thick potions 10 b, 10 c. Therefore, since it is difficult to deform the pressing portion 10 a in comparison with the embodiment shown in FIG. 1, the pressure portion 10 a can be engaged with the cylinder 100 hard.

FIG. 16 illustrates the sixth embodiment of the pressure pad 10. The pressure pad 10 has the supporting portions 10 f and the pressure portion 10 a which have thicknesses different from each other. The pressure portion 10 a is thinner than the supporting portions 10 f. That is to say, the pressure portion 10 a is thinner than the portion nipped by the support bar 40 and side plate 50. The pressure portion 10 a is thin to deform easily when engaging with the cylinder 100. Therefore, in comparison with the embodiment shown in FIG. 1, the pressure portion 10 a can be engaged with the cylinder 100 softly.

The thickness of the pressure portion 10 a has a relation with the necessary time for cleaning by the cylinder cleaning device 1 and the amount of consumption of the cleaning fabric during cleaning. However, it is preferable to determine the most appropriate thickness by the experiments.

FIG. 17 illustrates the seventh embodiment of the pressure pad 10. The pressure pad 10 includes the pressure portion 10 a and the thick portions 10 b, 10 c which are formed integrally. The pressure pad 10 does not have to be made of single material. In the embodiment shown in FIG. 17, the pressure pad 10 is made of two materials 10 h, 10 k. It is advantageous to select suitable materials for the pressure portion 10 a and the thick portions 10 b, 10 c respectively from two or more materials. For example, the material 10 h of the portion including the pressure portion 10 a can be made of soft material having low hardness, the material 10 k of the portion including the supporting portions 10 f can be made of hard material having high hardness. As a result, a soft press can be obtained without lowering the thickness of the pressure portion 10 a. The pressure pad 10 can be made of two materials which are superimposed on each other in the thickness direction, to achieve a certain property such as elasticity which cannot be provided by single material.

DESCRIPTION OF THE REFERENCE CHARACTERS

1 cylinder cleaning device

4 cleaning fabric

8 solenoid

10 pressure pad

10 a pressure portion

10 b, 10 c thick portion

10 d, 10 e connecting portion

10 f supporting portion

13 pipe

14 nozzle

40 support bar

41 base portion

42, 43 grooved portion

44 pressure pad shape holding wall

50 side plate 

1. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad made of elastic material and including a pressure portion engaged with the surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad, the pressure portion being interposed between and formed integrally with the thick portions; a support bar including grooved portions formed in the opposite sides thereof and extending longitudinally of the support bar, the thick portions being fitted into the grooved portions so that the pressure pad can be mounted on the support bar; and a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof, the pressure pad and the support bar being nipped between and held by the engaged portions.
 2. The cylinder cleaning device according to claim 1, wherein the pressure pad is plate-shaped, the pressure portion being bent to be generally semi-cylindrical so that the thick portions oppose to each other to be fitted into the grooved portions when the pressure pad is mounted on the support bar.
 3. The cylinder cleaning device according to claim 1, wherein the pressure portion is generally semi-cylindrical, the thick portions being opposed to each other to be fitted into the grooved portions.
 4. The cylinder cleaning device according to claim 1, wherein the side plate includes an opening on one side, the pressure pad and the support bar being received in the opening.
 5. The cylinder cleaning device according to claim 1, wherein the pressure pad and the support bar are nipped between the engaged portions on opposite sides thereof.
 6. The cylinder cleaning device according to claim 1, wherein the thick portions is generally cylindrical to extend longitudinally of the pressure pad.
 7. The cylinder cleaning device according to claim 1, wherein the pressure portion includes a pipe and nozzles, the pipe directing a cleaning liquid to the nozzles to supply the cleaning liquid toward the cleaning fabric engaged with the pressure portion.
 8. The cylinder cleaning device according to claim 1, wherein the pressure pad includes connecting portions formed between the pressure portion and the thick portions, the pressure portion being thicker than the connecting portions.
 9. The cylinder cleaning device according to claim 1, wherein the pressure pad includes connecting portions formed between the pressure portion and the thick portions and nipped between the support bar and the engaged portions, the pressure portion being thinner than the connecting portions and the thick portions.
 10. The cylinder cleaning device according to claim 1, wherein the pressure pad comprises two or more parts made of materials different in property from each other, the parts being formed integrally to each other.
 11. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad made of elastic material and including a pressure portion engaged with the surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad, the pressure portion being interposed between and formed integrally with the thick portions; a support bar including grooved portions formed in opposite sides thereof and extending longitudinally of the support bar, the thick portions being fitted into the grooved portions so that the pressure pad can be mounted on the support bar; and a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof, the pressure pad being shaped to be generally semi-cylindrical when being mounted on the support bar, the pressure portion including an outer surface disposed inwardly of the outer surface of the side plate when being shaped to be semi-cylindrical.
 12. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad made of elastic material and including a pressure portion engaged with the surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad, the pressure portion being interposed between and formed integrally with the thick portions; a support bar including grooved portions formed in opposite sides thereof and extending longitudinally of the support bar, the thick portions being fitted into the grooved portions so that the pressure pad can be mounted on the support bar; and a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof, the support bar including opposite side surfaces, the thick portions including outer surfaces disposed to be flush with the opposite side surfaces of the support bar when being fitted into the grooved portions to be nipped by the side plate.
 13. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad made of elastic material and including a pressure portion engaged with the surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad, the pressure portion being interposed between and formed integrally with the thick portions; a support bar including a base portion and grooved portions, the base portion having two parallel surfaces, the grooved portions being formed on the opposite sides of the support bar and extending longitudinally thereof, the thick portions being fitted into the grooved portions so that the pressure pad can be mounted on the support bar; and a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof, the pressure pad and the support bar being nipped between and held by the engaged portions, the base portion being nipped between the engaged portions, the thick portions being nipped and fixed between the grooved portions and the side plate.
 14. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad made of elastic material and including a pressure portion engaged with the surface of the cleaning fabric and thick portions formed at the opposite edges of the pressure pad, the pressure portion being interposed between and formed integrally with the thick portions; a support bar including a base portion and grooved portions, the base portion having two parallel surfaces, the grooved portions being formed on opposite sides of the support bar and extending longitudinally thereof, the thick portions being fitted into the grooved portions so that the pressure pad can be mounted on the support bar; and a side plate including engaged portions disposed on the opposite sides of the thick portions and engaged with the side surfaces thereof, the pressure pad and the support bar being nipped between and held by the engaged portions, the side plate being face-contacted with the thick portions and the base portion so that the thick portions oppose to each other to be fitted into the grooved portions when the pressure pad is mounted on the support bar.
 15. A cylinder cleaning device which cleans a cylinder by pressing a cleaning fabric against the outer surface of the cylinder, the device comprising: a pressure pad including a pressure portion, a pair of thick portions and a pair of connecting portions, the pressure portion being disposed on the center of the pressure pad and engaged with the surface of the cleaning fabric, the thick portions being disposed on the opposite edges of the pressure pad, the connecting portions being interposed between the pressure portion and the thick portions to connect the pressure portion with the thick portions and being thinner than the thick portions, the pressure portion, the thick portions and the connecting portions being made of elastic material and formed integrally; a support bar including a base portion and a pair of grooved portions, the base portion extending longitudinally of the support bar, the grooved portions being formed in the opposite sides of the base portion to extend longitudinally of the support bar and having depths corresponding to the thicknesses of the thick portions and corresponding to the thickness of the connecting portions so that the thick portions and the connecting portions can be fitted into the grooved portions, the thick portions and the connecting portions including outer surfaces disposed to be flush with the opposite sides of the base portion when the thick portions and the connecting portions are fitted into the grooved portions; a side plate including engaged portions engaged with the opposite side surfaces of the base portion and the outer surfaces of the thick and connecting portions; and a fixing means adapted to fix the side plate on the base portion.
 16. The cylinder cleaning device according to claim 15, wherein the thick portions project toward the grooved portions from the inner surface of the connecting portions. 